Liquid nitrate ester monopropellant composition

ABSTRACT

A liquid nitrate ester monopropellant composition comprising triethylene glycol dinitrate, metriol trinitrate and a storage stabilizer. No inert diluents are incorporated therein.

United Mates Patent represented by the Secretary of the Navy LIQUID NITRATE ESTER MONOPROPELLANT COMPOSITION 7 Claims, No Drawings US. Cl 149/88,

149/105 Int. Cl C061) 3/00 Field of Search 149/88,

References Cited UNlTED STATES PATENTS Austin Sampson Matuszko et a1.. Crescenzo et a1. Bronstein et a1. Hopper et al7 Schwoyer Primary ExaminerCarl D. Quarforth Assistant Examiner-Stephen J. Lechert, Jr. AtlorneysR. S. Sciascia, J. A. Cooke and R. .1. Erickson 149/88 149/88 X 149/88 X 149/88 X 149/88 X 149/88 X ABSTRACT: A liquid nitrate ester monopropellant composition comprising triethylene glycol dinitrate, metriol trinitrate and a storage stabilizer. N0 inert diluents are incorporated therein.

LIQUID NITRATE ESTER MONOPROPELLANT COMPOSITION BACKGROUND OF THE INVENTION This invention relates generally to liquid monopropellants and more particularly to nitrate ester liquid monopropellants, which are especially useful for underwater propulsion.

Basically, liquid monopropellants are composed of either of the following: (1) a mixture of a combustible material and oxidizing agent that will undergo an exothermic chemical reaction or (2) a single chemical which will release energy through exothermic decomposition and/or recombination. Recently, tremendous success has been achieved with the discovery of certain new liquid nitrate ester compositions of this second type. However, these prior art nitrate ester monopropellant compositions employ organic inert diluents in amounts ranging up to about 20 percent of the total composition. These diluent materials adversely affect the combustion efficiencies of the respective monopropellant compositions since their presence results, fundamentally, in a two step process in which the nitrate ester is first burned, followed by the combustion of the inert diluents; obviously, a more efficient one step combustion procedure is desirable.

Other disadvantages of prior art liquid nitrate ester monopropellant compositions are their higher than desirable freezing points and toxicity due to the higher than desirable volatility of these nitrate esters. Both of these disadvantages pose serious problems in the handling and storage of these compositions.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a new energetic liquid nitrate ester monopropellant composition.

Another object of this invention is to provide a liquid nitrate ester monopropellant which does not utilize inert diluents and which provides a higher combustion efficiency than those previously available.

Still another object of this invention is to provide a liquid nitrate ester monopropellant which has improved low temperature capabilities, i.e. lower freezing point, and reduced toxicity due to reduced volatility.

These and other objects are achieved by providing a monopropellant composition comprising a solution of a low volatile energetic nitrate ester such as triethylene glycol dinitrate (TEGDN) and another low volatile energetic nitrate ester such as metriol trinitrate (MTN) which also further acts as a freezing point depressant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention will be better understood by the following examples of compositions, which possess the hereinbefore disclosed advantages:

EXAMPLE I Composition weight triethylene glycol dinitrate (TEGDN) 94.9 metriol trinitrate (MTN) 5.0 ethyl centralite 0.1

EXAMPLE II Composition weight triethylene glycol dinitrate (TEGDN) 89.9 metriol trinitrate (MTN) 10.0 ethyl centralite 0. 1

EXAMPLE III Composition weight triethylene glycol dinitrate (TEGDN) 84.9

metriol trinitrate (MTN) 15.0 ethyl centralite 0.1

As is evident from the above examples, the monopropellant compositions of the present invention do not employ inert diluents. These compositions are of reduced shock sensitivity, reduced toxicity, and possess low-freezing points. The lack of inert diluents allows for a more efficient one step physical combustion process since the burning of residual diluent materials is obviated. Of course, material other than those illustrated in the compositions of examples I through III are operable herein for the purposes of this invention. For example, low volatile diethylene glycol dinitrate (DEGN) may be substituted for the triethylene glycol dinitrate, while low volatile 1,4-butylene glycol dinitrate and diethylene glycol dinitrate may be used in place of the metriol trinitrate. Stabilizing materials, such as methyl centralite and 2-nitrodiphenylamine (NDPA), may be substituted for the ethyl centralite.

The quantities of the materials incorporated in the monopropellant compositions of this invention may vary within a wide range. For instance, the triethylene glycol dinitrate and those materials which may be substituted therefor may be present in amounts ranging from about to about 5 weight percent of the total composition, while the metriol trinitrate and those materials which may be substituted therefor may be present in amounts ranging from about 5 to 95 percent by weight of the total composition. The stabilizing material is usually present in amounts from about 0.1 to about 1.0 weight percent. Very low contents of stabilizers are feasible in this invention because of the inherently high stability of the all-primary nitrate esters used.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed and desired to be secured by Letters Patent of the United States is:

l. A liquid monopropellant comprising the mixture of a low volatile liquid energetic nitrate ester selected from the group consisting of triethylene glycol dinitrate and diethylene glycol dinitrate and another low volatile liquid energetic nitrate ester selected from the group consisting of a metriol trinitrate and 1 ,4-butylene glycol dinitrate and a stabilizer.

2. A liquid monopropellant comprising a mixture of triethylene glycol dinitrate,

diethylene glycol dinitrate and a stabilizer.

3. The monopropellant of claim 1 wherein the first of said low volatile liquid energetic nitrate esters is triethylene glycol dinitrate and the second of said low volatile liquid energetic nitrate esters is metriol trinitrate.

4. The monopropellant of claim 1 wherein the first of said low volatile liquid energetic nitrate esters is present in an amount of from about 95 to about 5 percent by weight of the total composition and the second of said low volatile liquid nitrate esters is present in amount of from about 5 to about 95 percent by weight of the total composition and said stabilizer is present in an amount of from about 0.l to about 1.0 percent by weight of the total composition.

5. The monopropellant of claim 1 wherein said stabilizer is selected from the group consisting of ethyl centralite, methyl centralite and 2-nitrodiphenylamine.

6. The monopropellant of claim 2 wherein said triethylene glycol dinitrate is present in an amount of from about 95 to about 5 percent by weight of the total composition, wherein said diethylene glycol dinitrate is present in an amount of from about 5 to about 95 percent by weight of the total composition and said stabilizer is present in an amount of from about 0.1 to about 1.0 percent by weight of the total composition.

7. The monopropellant of claim 2 wherein said stabilizer is selected from the group consisting of methyl centralite, ethyl centralite and 2-nitrodiphenylamine. 

2. A liquid monopropellant comprising a mixture of triethylene glycol dinitrate, diethylene glycol dinitrate and a stabilizer.
 3. The monopropellant of claim 1 wherein the first of said low volatile liquid energetic nitrate esters is triethylene glycol dinitrate and the second of said low volatile liquid energetic nitrate esters is metriol trinitrate.
 4. The monopropellant of claim 1 wherein the first of said low volatile liquid energetic nitrate esters is present in an amount of from about 95 to about 5 percent by weight of the total composition and the second of said low volatile liquid nitrate esters is present in amount of from about 5 to about 95 percent by weight of the total composition and said stabilizer is present in an amount of from about 0.1 to about 1.0 percent by weight of the total composition.
 5. The monopropellant of claim 1 wherein said stabilizer is selected from the group consisting of ethyl centralite, methyl centralite and 2-nitrodiphenylamine.
 6. The monopropellant of claim 2 wherein said triethylene glycol dinitrate is present in an amount of from about 95 to about 5 percent by weight of the total composition, wherein said diethylene glycol dinitrate is present in an amount of from about 5 to about 95 percent by weight of the total composition and said stabilizer is present in an amount of from about 0.1 to about 1.0 perCent by weight of the total composition.
 7. The monopropellant of claim 2 wherein said stabilizer is selected from the group consisting of methyl centralite, ethyl centralite and 2-nitrodiphenylamine. 